Estrogen related receptors (ERRs): A new dawn in transcriptional control of mitochondrial gene networks

Mitochondrial dysfunction contributes to the etiology of numerous diseases. Consequently, improving our knowledge of how to modulate mitochondrial activity is of considerable interest. One means to achieve this goal would be to control in a global and comprehensive manner the expression of most if not all nuclear encoded mitochondrial genes. The advent of genome-wide location analysis of transcription factor occupancy coupled with functional studies in cell and animal models has recently shown that three transcription factors possess this unique attribute. Unexpectedly, these factors are orphan members of the superfamily of nuclear receptors known as estrogen-related receptors (ERRs) α, β and γ. In this review, we will integrate current knowledge gathered through several functional and physiological genomic studies to provide persuasive evidence that the ERRs are indeed master regulators of mitochondrial biogenesis and function.